Upon mining ore or the like at a mine, for example, an excavator having an excavation means for soil and rocks and haulage machines, such as dump trucks, for hauling materials excavated by the excavator are brought into the mining site. Excavated ore is loaded on dump trucks as the haulage machines and is hauled out of the mining site. For the purpose of mining, large-scaled hydraulic shovels are used as the excavators having their bucket capacity of 3 m3 to 40 m3 or more. Even if dump trucks of large capacity are also used, the vessel of each dump truck is, therefore, filled up with excavated materials loaded one to several times or so from the corresponding bucket. Therefore, plural haulage machines are kept in readiness for each loading machine, and are successively delivered to the side of the loading machine.
In a case where a haulage machine and an excavator are not arranged in proper positional relation upon loading excavated materials such as ore from the excavator to the haulage machine, time is wasted in the loading work so that the efficiency of the work is lowered. After a haulage machine, such as a dump truck, has traveled out of a loading position with its vessel being filled up, a new haulage machine is approached for a replacement. The mining work should be interrupted while the dump truck is being replaced. In order to bring the haulage machine to the proper position, steering or the like may be repeated right and left until the new haulage machine is placed at the proper position, a large time should be spent until the new haulage machine is placed at the proper position, so that the efficiency of the work is also lowered.
In the event that a haulage machine is moved to the final position, the haulage machine is normally driven backwardly to allow its vessel to be closed at a suitable loading position from an excavator. In the case of a dump truck for ore haulage, a backward field of vision from its driver's seat can only be obtained from a rearview mirror, so that an operation to place the dump truck at a proper position by reversing it involves further difficulties. In this respect, for example, Patent Document 1 is disclosed a construction that to obtain a field of vision to the rearward side of a vehicle, a back eye camera is mounted on a rear position of the vehicle, a back eye display is arranged in a cab, and an image of the rearward side of the vehicle from the back eye camera is displayed on the back eye display.